Conventionally, a reactive hot-melt adhesive composition containing: (A) a graft polymer formed by copolymerizing one type or two or more types of monomers selected from the group consisting of polystyrene-based macromers having a vinyl group at a molecular terminal, alkyl acrylates in which an alkyl group has 1 to 12 carbons, and alkyl methacrylates in which an alkyl group has 1 to 12 carbons, (B) polyol, and (C) polyisocyanate has been proposed, and it is described that the composition can contain a plasticizer or the like (Japanese Unexamined Patent Application Publication No. H05-017736A).
However, the inventor of the present application found that conventional reactive hot-melt adhesives may not satisfy the level of adhesion (especially, water resistant adhesion) that has been required recently.